Ros or ROS or RoS may refer to:

• Raggruppamento Operativo Speciale, the Anti-organized Crime Branch of the Italian Carabinieri
• Registers of Scotland, a Scottish authority responsible for compiling and maintaining records
• Reparti i Operacioneve Speciale, a former Albanian special forces unit
• IL ROS, Norwegian football team

• Scottish Gaelic spelling of the name Ross
• Baron de Ros

• Ana Ros Camacho, Spanish mathematician
• Arno Ros (born 1942), German philosopher
• Carmen Ros Nortes (born 1953), Catholic nun and Vatican official
• Edmundo Ros (1910–2011), Trinidadian-British musician
• Enrique Ros (1924–2013), Cuban-American businessman and activist
• Fran Roš (1898–1976), Slovene writer
• Giuseppe Ros (1942–2022), Italian boxer
• Iñigo Ros (born 1982), Spanish footballer
• Isidro Ros Ríos (born 1995), Spanish footballer
• Jaime Ros, (born 1952), Spanish alpine skier
• Javier Ros (born 1990), Spanish footballer
• José Ros García (1920–2001), Spanish poet
• Lázaro Ros (1925–2005), Cuban singer
• Ramón Ros (born 1981), Spanish footballer
• Richard Ros (born 1429), English poet
• Amanda McKittrick Ros (1860–1939), Irish writer
• Mohd Remezey Che Ros (born 1982), Malaysian footballer
• Uilleam Ros, Scottish Gaelic poet
• Juan Antonio Ros (born 1996), Spanish footballer
• Ros Saboeut (c. 1942–2014), Cambodian musician
• Ros Serey Sothea (1948–1977), Cambodian singer
• Ros Sopheap (born 1962), Cambodian women's rights activist

• Ros Atkins (born 1974), British journalist
• Ros Bates (born 1962), Australian politician
• Ros Childs (born 1967), British journalist
• Ros Drinkwater (born 1944), Scottish actress
• Ros Evans (born 1960), British athlete
• Ros Kelly (born 1948), Australian politician
• Ros Kember (born 1985), New Zealand cricketer
• Ros Pesman (born 1938), Australian historian
• Ros Spence (born 1970), Australian politician
• Ros Myers, fictional character

• Lake Roś, Poland
• Republic of Singapore, a country in South-East Asia
• Reserve Officer School, a conscript training facility in Finland
• Ros, Belarus, an urban-type settlement in Grodno Region, Belarus
• Ros (river), Ukraine

• Reactive oxygen species, chemically reactive molecules containing oxygen
• ReactOS, a free and open-source operating system intended to be binary-compatible with Windows NT
• ROS1, receptor tyrosine kinase
• ROS, a weak signal sound card mode for Amateur Radio
• Rod outer segment, the light-sensitive part of the retina of the eye
• Robot Operating System, an open-source robotics platform by Willow Garage and Stanford AI Labs
• ROM Operating System, a ROMed version of Digital Research's DR DOS
• Russian Orbital Segment, components of the International Space Station
• Random orbital sander, also called palm sander, a hand-power tool

• Rosanna railway station, Melbourne
• Rosario – Islas Malvinas International Airport, Argentina
• Rosyth railway station, Fife, Scotland (National Rail station code)

• Ros (grape), another name for the wine grape Mourvèdre
• Ros (vehicles), a Greek light truck manufacturer
• Reaper of Souls, an expansion to the game Diablo 3
• Return on sales, an accounting ratio that detects operational efficiency
• Review of systems, medical
• Star Wars: The Rise of Skywalker, a 2019 film

• Ross (disambiguation)
• Da Ros, surname
• Rosas (surname), of which Ros is a spelling variation
• Rot
• RDOS (disambiguation)
• ROTS
• Tros